What’s the difference between Brentwood XF75 cooling tower fill supports and using repurposed PVC shipping pallets?
That’s a good question and one we get asked frequently by owners. While cutting down plastic shipping pallets and using them as fill supports for factory assembled crossflow fill repacks is probably the cheapest method to support the fill, that’s about the only thing it has going for it. The use of cheap PVC shipping pallets for fill supports most likely came about because tower rebuilders were looking for cost savings rather than evaluating the potential results for the owner or understanding the differences in PVC quality. PVC pallets are cheap because they are basically throwaway products, manufactured overseas with the lowest grade PVC available. At no point in their design are they engineered for use in a cooling tower environment or to have a long lifespan.
Brentwood’s XF Support systems are engineered specifically for cooling towers and to handle the temperatures, loads, and longevity expected for these specific applications. The multitude of engineered configurations allows for project-specific designs to fit the fill pack and DE arrangement of every tower and to provide one unitized support from endwall to endwall (as opposed to costly field cutting and non-engineered retainer systems with cheap pallets that are placed side-by-side and have increased potential for movement over time). The Brentwood XF supports provide the same factory quality installation on every project. They are designed to work with basin cleaning systems and to drastically eliminate any debris hang-up points while allowing for easy sweeper system installation and clearance.
Cheap pallets also have the disadvantage of multiple “feet” that contact the basin floor for support, trapping dirt and making basin sweeper systems ineffective. Many installations have shown that these “feet” retain stagnant water and are a breeding ground for biologicals in the system that are extremely difficult to treat, eliminate, or even contain. Where the bottom of these “feet” are cut to allow for drainage in order to prevent this (which is proof that there is concern for bio growth), you are left with rings of plastic to support the fill packs. This puts tremendous point loading on the cold water basin floor as well as extreme pressure on the low-quality plastic. Simple calculations of the fill weight plus fouling weight and water weight give us a result that the cheap plastic pallet design may need to withstand upwards of 68.2lbs/square inch! It certainly would not be common for either the plastic pallet material or the cooling tower cold water basin to be designed for this amount of point loading. The Brentwood XF supports are designed for this consideration, and with the same weight loading, would apply 5.5lbs/square inch to the cold water basin. That’s a 92% reduction in loading!
Just one callback to a job site because of a failure of the fill supports or because of excessive deflection in the cold water basin pan would no longer makes these “cheap” shipping pallets the cost-effective option for the contractor or the owner. Nothing good comes cheap. If it’s worth doing, then it’s worth doing right the first time!